The present invention relates to ultrasound systems which measure and image anatomical structures. More particularly, the present invention relates to a method and apparatus for detecting the position and orientation of an ultrasound probe with respect to an ultrasound phantom, to be used in an ultrasound training system.
Ultrasound imaging systems are highly complex and sophisticated devices. System operators must be specially trained in the operation of ultrasound imaging systems in order to ensure that accurate and useful information is obtained. Training systems that provide feedback on operator technique would be useful in the training of ultrasound system operators.
Knowledge of the position and orientation of a sensor relative to a known coordinate system is useful in various fields such as in medical imaging. For example, because proper ultrasound visualization depends upon probe position and orientation, the detection of the position and orientation of an ultrasound probe relative to an imaged object is useful in an ultrasound training system.
Currently systems utilize positioning devices that are based on magnetic fields, optics or special electronic devices. For example, U.S. Pat. No. 5,609,485 discloses a system that may be used for ultrasound training wherein position and orientation information is utilized. In this system, the position and angle of an ultrasound probe (or a simulated probe) is detected by a separate positioning device that operates independently of the ultrasound system. This positioning device utilizes a transmitter/receiver pair having three antennae each that operate on magnetic field principals. The transmitter is mounted on or near a human body or mannequin while the receiver is located on the probe. When used in connection with a real ultrasound system in a data collection mode, the position information generated by the positioning device is stored in a virtual ultrasound database along with ultrasound image information corresponding to the detected position of the probe. When used in connection with a simulated ultrasound system for training, the position information is monitored and a simulated ultrasound image is simultaneously displayed using information from the virtual ultrasound database that corresponds to the position of a simulated probe.
A disadvantage of using independently operating positioning devices such as the kind described above is that use of separate positioning hardware adds to the level of complexity and cost of the system, such as an ultrasound training system. A further disadvantage is that the magnetic field used to detect probe position may interfere with, or be affected by, the imaging equipment. Still further, such positioning devices only measure position with respect to the transmitter, which is mounted on or near the imaged object. If the transmitter is not mounted in a proper position with respect to the imaged object, the probe position indicated by the positioning device may be different from the actual probe position.
A need remains for an improved manner of detecting probe position and orientation to overcome the above-identified difficulties. It is an object of the present invention to meet this need.